Substituted alkadienes, especially alpha-substituted alkadienes, such as octadien-1-ol have numerous utilities including as chemical intermediates to make alcohols and esters useful in the electroplating, plastics, perfume and pharmaceutical industries and as microbials. Considerable efforts have been expended by numerous researchers to develop cost advantaged processes for the synthesis of alpha-substituted alkadienes, e.g., octadien-1-ol.
A much suggested synthesis of alkadienes involves the telomerization of conjugated diene in the presence of water and homogeneous palladium-containing catalyst. See, for instance, U.S. Pat. Nos. 3,534,088 and 3,711,534. Palladium catalyst, however, is expensive and workers in the field have thus devoted considerable efforts to reduce the amount of palladium required and/or improve recovery of active, homogeneous catalyst from the alkadiene product in order to achieve commercial viability. Particular attention has been devoted toward
a. increasing the activity of the palladium catalyst to minimize the concentration of palladium in the reaction menstruum, PA1 b. enhancing selectivity to synthesize alkadien-1-ol, PA1 c maintaining the activity of the catalyst to avoid frequent catalyst regeneration procedures, PA1 d. reducing temperature sensitivity of the catalyst, and PA1 e. efficiently recovering the catalyst from the products for recycle without unduly adverse effect on its catalytic properties.
A particularly troublesome problem has been to obtain a catalyst which excels in activity, selectivity, efficiency of recovery and stability. For instance, the use of phosphine in the reaction menstruum in high ratios with respect to palladium present results in catalysts with enhanced stability but at the cost of selectivity and activity.
U.S. Pat. No. 4,774,361 discloses the use of organic polymer additive to minimize or prevent the rhodium of a rhodium organophosphite complex catalyst from precipitating from solution during a liquid recycle hydroformylation process. This patent provides no disclosure relating to the synthesis of alpha-substituted alkadienes or to palladium-containing catalysts.